KEY AND INDEX 



Muscular System. The term applied to all muscles of the body 

 as distinguished from the nervous system, osseous system, etc. 



Nautical Almanac. An almanac published by the United 

 States and other maritime powers, for the use of astronomers 

 and navigators, in which is given the angular distances of the 

 moon from the sun, planets, and fixed stars, etc., and other in- 

 formation that enables the navigator to determine exact posi- 

 tions of latitude and longitude. See "The Conquest of the 

 Zones," Vol. VII, p. 37. 



Neolithic Civilization. A term applied especially to the civiliza- 

 tion of northwestern Europe during the epoch of highly finished 

 and polished stone implements. It was the later period of the 

 "stone age," the earlier period being the Paleolithic age. 



Neon. A gaseous element discovered in the earth's atmos- 

 phere by Ramsay and Travers in 1808. See "Some Physical 

 Laboratories and Physical Problems," Vol. V, p. 84. 



Neptune, (i) In Roman mythology the god of the sea; 

 (2) in astronomy the most distant of the known planets. It is 

 peculiar in revolving from east to west, and revolves around 

 the sun in 164.6 years. See "The Discovery of Neptune," Vol. 



III, p. 42- 



Neptunists. The name given to the followers of Werner of 

 Saxony, who believed that "in the beginning all the solids of the 

 earth's crust were dissolved in the heated waters of a universal 

 sea." The opponents of this theory, who followed James Hut- 

 ton's teachings, were called "Plutonists." See "Neptunists 

 versus Plutonists," Vol. Ill, p. 131. 



Nerve Cells. Structures in the brain from which the nerve- 

 filaments originate. They may be likened to "a central tele- 

 phone office of a telephone system." See "The New Science 

 of Experimental Psychology," Vol. IV, p. 249. 



Nerves. Filaments leading from the nerve cells of the brain 

 to various structures of the body, such as muscles, glands, etc., 

 which serve as conductors of impulses, to and from the brain. 

 Sir Charles Bell, in 1811, discovered that there are two distinct 

 sets of nerves, one for carrying motor and the other for carry- 

 ing sensory impulses. See "Experimental Psychology," Vol. 



IV, p. 249- 



Nitrate Beds. Large areas in northern Chili, Peru, and Bo- 

 livia, containing sodium nitrate (Na N O,) in a native state. 

 This substance is valuable as a fertilizer, and as a source of 



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